[rvitko]

Thank you very much for this thorough review.

For the pH probe fitting, I would contact Tunze for replacement, this should not be, we use really the same port I have seen typically used and I don't know of another, it seems all use the same port, I have to assume it is bad or maybe needs some teflon tape at the thread.

I have 2 3170 running in tandem in my tank, this product was never actually made for the public because they decided a better design could be made with some time. I am happy with them but I notice the same as you regarding drip rate. My observation is that their is a delay, so make the settings slowly and wait a minute at least before more adjustment, and the adjustment changes a very little with the pressure of the CO2 being added so it is less when CO2 is off. In either case I have not found it to be a big problem and I generally find the drip is more stable than the conventional drip setting on output.

I have been told to avoid the medias which are not like ours only because the medias made of coral skeletons tend to dissolve incompletely leaving a mushy residue which clogs the pump and inside so the limestone or marble type media is cleaner. The draw back of course is less Mg and Sr and a lower pH is needed to dissolve it, closer to 6.5. I am using our Calcium Carbonate media and it has given good results, paired with kalkwasser I very consistently keep a KH of 10-12 degrees, almost always 10.5-11.5 and Calcium is always 420-450.